Announcements have been used for decades to communicate information to users waiting in a contact center queue. Customers typically expect to hear music on hold and estimated wait time information. When there is a workflow in progress (e.g., a series of messages to be played), there are times in the workflow that the music on hold message is interrupted to play a short announcement. Once the short announcement is completed, an event message may come back from a media server to say that the announcement is complete. The workflow then resumes based on the receipt of the event message. For example, interrupting music on hold while the user is on hold in the contact center queue to give an estimated wait time for the call to be answered is a common event. When the workflow is interrupted, the music temporarily stops, the announcement is played, and then the music resumes until an agent accepts the work item.
If a primary server controlling the call fails during the short interrupt announcement, the event message from the media server saying that the announcement is complete may get lost. Rather than hearing the music resume, the customer may hear silence. If a customer hears silence for too long before a failover completes and a new application server takes over and resumes the workflow, the customer may hang up.